1. Field of the Invention
The present invention relates to an automatic coating system for automatically coating a coating material on an object to be coated.
2. Description of the Related Art
The manufacture of semiconductors includes a step of coating a resist on a wafer. This step is executed by use of the apparatus disclosed in Japanese Patent Publication No. 53-37189, for example. According to this reference, a wafer is mounted on a spinning head arranged in a processing vessel and is temporarily secured on the spinning head by suction. In this condition, a resist solution is supplied on the surface of the wafer while simultaneously rotating the wafer.
In this apparatus, a series of coating operations to be executed are programmed beforehand in a program unit, and the programmed steps are sequentially, successively performed to coat a coating material on a wafer. That is, resist coating is performed by the following series of steps. First, a wafer conveyed by a conveyor apparatus is centered on a spinning head and temporary chucked on the head by vacuum suction, and a cup is set to prevent scattering of a resist solution. Thereafter, while the head is rotated, the resist solution is dropped and a coating operation is performed. In this case, since the resist solution or the like adheres on the rear surface of the wafer upon resist coating, the adhered material must be removed in the coating apparatus before it is brought into contact with the conveyor apparatus. For this purpose, a cleaning nozzle is arranged to clean the wafer rear surface. After the resist is coated, a cleaning solution is injected from the cleaning nozzle to the rear surface of the wafer while the wafer is rotated, thereby cleaning the wafer rear surface.
In such a conventional apparatus, the above series of operations of coating a resist solution on a wafer can be successively executed without any problem. However, if it is required that the apparatus be adjusted or checked for maintaining a desirable condition, the apparatus must be stopped for some time, with the step executed by the apparatus kept in a suspended condition.
In the conventional coating apparatus, however, an operation cannot be stopped during the coating steps. Therefore, in order to stop the operation to perform adjustment, a power source must be turned off. As a result, when adjustment is to be performed while properness of the operation is checked in each step, an operability becomes very poor, and a long time is required for the adjustment, resulting in a cumbersome operation for an operator.